The Base URI (e.g. http://www.myserver.com/psp/mysite/) is only available automatically in the context of a web server. If a process is not signed in via the web (e.g. Application Engine), the Node definition specified in the function is checked for that Base URI. Open the Node Definition (PeopleTools > Portal > Node Definitions) and enter the Content URI (.../psc/...) and Portal URI (.../psp/...) on the Portal page. These are used by the GenerateComponentContentURL and GenerateComponentPortalURL functions, respectively. By default these fields are empty.